Character() formula wraps a 0xffff and can't produce all unicode characters

[Einar_Boson]

For whatever reason, I’m trying to display something graphically unique to a specific row. To do this, I wanted to use hieroglyphics, like these: 𓀂 𓀄 𓀇 𓂓 𓂔 𓂕.
Should be simple. just a formula involving Character(), but Character(77827) (0x13003) results in 〃 which is character 12291 (0x3003).

The range of Character() is not all of unicode it would seem. It seems to wrap at 0xffff. Can that be fixed? Or at the very least documented.

Thank you